The paper has analyzed influence of additives representing a group of thermoplastic elastomers and complex thermoplast-based modifiers on fatigue life of asphalt concrete. Regularities in time have been determined in the paper and close values of their physical and mechanical properties have been obtained while using various types of binders and modifiers. Statistic and laboratory investigations have made it possible to obtain theoretical parameters of the fatigue life for materials used for road dressing. The analysis has been based on statistical values of ordinary and modified asphalt concrete and asphalt concrete mixes of C- and A-type obtained during the experiments for the period from 2010 till 2016. A statistic analysis has permitted to compare a parameter И_пл (resistance index to plastic deformations) with such parameters as n_y (number of elastic constraints) and R_c (threshold structural strength). 12 calculations (Nos. 1–12) have been carried out in order to realize targets of the second investigation. Calculative characteristics of asphalt concrete required for determination of reliability parameters have been estimated in the paper. A bottom layer of twoor three-coat pavement has been selected as an object of the investigation due to the fact that it is more often subjected to an impact of cyclic tensile stresses caused by a transport load. The required value for calculation of tensile stresses s at calculated temperature 0 has been accepted on the basis of executed estimations while using finite elements method and distribution of stresses has been determined along structure with 20 cm thickness due to load А₂. Corresponding conclusions have been made in accordance with the obtained results.

The paper presents solutions of two contact problems for the annular plate die on an elastic half-space under the action of axisymmetrically applied force and moment. Such problems usually arise in the calculation of rigid foundations with the sole of the annular shape in chimneys, cooling towers, water towers and other high-rise buildings on the wind load and the load from its own weight. Both problems are formulated in the form of triple integral equations, which are reduced to one integral equation by the method of substitution. In the case of the axisymmetric problem, the kernel of the integral equation depends on the product of three Bessel functions. Using the formula to represent two Bessel functions in the form of a double row on the works of hypergeometric functions Bessel function, the problem reduces to a functional equation that connects the movement of the stamp with the unknown coefficients of the distribution of contact stresses. The resulting functional equation is reduced to an infinite system of linear algebraic equations, which is solved by truncation. Under the action of a moment on the annular plate  die, the distribution of contact stresses is searched as a series by the products of the Legendre attached functions with a weight corresponding to the features in the contact stresses at the die edges. Using the spectral G. Ya. Popov ratio for the ring plate, the problem is again reduced to an infinite system of linear algebraic equations, which is also solved by the truncation method. Two examples of calculations for an annular plate die on an elastic half-space on the action of axisymmetrically applied force and moment are given. A comparison of the results of calculations on the proposed approach with the results for the round stamp and for the annular  stamp with the solutions of other authors is made.

Experience in the operation of prefabricated concrete pavements with intensive traffic of heavy vehicles has shown that despite a high strength of the concrete slabs themselves it is necessary to arrange strong foundations. While laying concrete on the ground residual deformations are accumulating in it due to pressures which are initiated by elastically bending plates when vehicles are passing that leads to formation of voids under the plate and cracks in the plate itself. In order to increase rigidity of the plate (reduction of its settlement during the passage of vehicles) the author has proposed to arrange plates with two longitudinal ribs, and the plates themselves are to be laid on loose soil mixed with cement. The ribs are proposed to be placed on roll bars, i. e. symmetrically with respect to a longitudinal axis of the plate at a distance from each other which is equal to the distance between wheels of the calculated vehicle on one axis. In order to determine dependence of plate rigidity on a shape and a size of a cross section in longitudinal ribs calculations have been made while using a PC “Lira” and a finite element method. A finite element model of the plate has included 19152 nodes and 18943 finite elements. An elastic foundation has been modeled by vertical elastic links which are in every bottom node. The plate has been loaded with a load which is equivalent to the load from a calculated vehicle wheel at four points: a wheel in the middle of the plate; a wheel on the corner of the plate; two wheels at the same time on the line which is perpendicular to the longitudinal axis of the plate and located at the beginning (or end) of the plate; two wheels at the same time on the line which is perpendicular to the longitudinal axis of the plate and passing through its center. The following forms of a longitudinal rib having the same crosssectional area have been studied at the beginning: triangular, oval (semicircle) and rectangular. In the context of plate rigidity increase the most optimal form has been a triangular shape. Height differences in such a plate are the least in case of load action. So, for example, in comparison with a typical plate (plate without longitudinal ribs), presence of longitudinal ribs of triangular cross – section increases plate rigidity by an average of 50 % depending on the location of the calculated wheel on the plate (39–64 %). After determining an optimal shape of cross section for longitudinal ribs the dependence has been found for plate rigidity and it depends on a height of longitudinal triangular ribs. While having a constant volume of the plate and a constant a size of the rib base (32 cm) (approximate width of a calculated vehicle wheel) a rib height and a plate thickness have been changed. The calculations have made it possible to determine dependence of the plate rigidity on a height of a longitudinal rib. It has been determined that as for the given volume and dimensions of the plate the optimal rib height is 25 cm.

Modern geotechnical pile manufacturing technologies allow to solve many engineering problems in construction with significant economic effect and reduction of work schedule. However a theoretical justification for these technologies is significantly lagging behind from their practical application. A constrained dilatancy factor is considered as the main reserve of pile bearing capacity in loose soils. Understanding of such approach opens a way to improvement of geotechnical pile manufacturing technologies that provide an active impact on base soil and its ultimate stress state which is determined by the ratio of soil resistance to shearing and normal stresses, or main stresses on a shear site at the moment of failure. Determination of total normal stresses in the shearing plane according to density of loose soil, its granulometric composition and constrained dilatancy conditions makes it possible to determine an ultimate resistance of the soil to shear, and, consequently, its strength. The proposed elastic-plastic model of dilatant soil in shear state being realized according to the adopted technology which was developed while using a special dilatometric shearing device has made it possible to obtain additional data on dilatant normal stresses and strength parameters of the soil depending on its density, granulometric composition and constrained dilatancy conditions. The use of artificial neural networks in the mathematical processing of experimental data has permitted to develop an analytical method for determining an ultimate resistance of loose soil to shearing process under constrained dilatancy conditions and carry out calibration of the calculated parameters of the adopted soil model. It has been proved that soil strength is a function of fracture conditions, which are determined by friction and dilatancy. In this case a conventional Coulomb-Mora strength theory for loose soils is valid both for free dilatation conditions and constrained shear but with due account of additional normal dilatant stresses.

Assessment of the current state in respect of various bank stabilization with identification of causes of their destruction and deformation scale has been carried out on the basis of the survey pertaining to coastal protection structures in more than 100 reservoirs of the country. The paper presents results of field observations on bank slope protection structures which are used at water reservoirs in Belarus. It has been established that the most common protection of banks and slopes is strengthening in the form of reinforced concrete monolithic or prefabricated slabs. It has been determined that deformations of slope protection are represented by opening of tile-to-tile construction, temperature and settlement joints (it has been recorded opening width of 0.35 m) which develop under a complex impact of wind waves, fluctuations in levels and other factors. Subsequently deformations of exposed joints lead to destruction of the protection. Value of slope deformations reaches in some cases rather significant extent: linear processing (destruction) of slopes – up to 24.20 m; volume of erosion – up to 4.25 m3/m running. Physical modeling of slope deformations carried out at a hydro-technical laboratory of the Belarusian National Technical University while using models of ground retaining structures protected by reinforced concrete strengthening with various opening width of joints has allowed to determine dynamics and scope of slope deformations due to the influence of wave and level regimes having various parameters. Data of on-site investigations on protection have made it possible to assess the state of slope paving for various operational periods of retaining structures. The paper presents reasons and factors that affect the protection stability. The results of on-site and laboratory investigations on protection stability have permitted to determine that the following reasons influence on the development of deformations: presence of objective inaccuracies and assumptions in the accepted calculated design schemes and dependencies for determination of protection parameters; lack of completeness in registration of conditions for wave formation and level regime of reservoirs; initial data and survey materials do not always provide true information about ground conditions for construction of bank protection facility; technological deviations while constructing structures and their protection. It has been ascertained that one of the characteristics determining a dynamic stability of banks and slopes in structures under conditions of the reservoirs in Belarus along with the above reasons is a composition of the eroded soil characterized, in particular, by a inhomogeneity coefficient of loose soil. A self-pavement effect identified during the study of protection stability and formed during destruction of a bank composed of loose soils with increased heterogeneity has made it possible to propose a method for protecting slopes and banks. On-site investigations and laboratory experiments have permitted to obtain empirical relationships for calculation of dynamic equilibrium profile with self-pavement of two types. The paper provides a calculation for combined slope protection consisting of rockfill and synthetic filter materials of increased strength.

Creation and development of scientific and technological parks in the People's Republic of China is used as a means of activating areas in need of socio-economic development, for example such territories as along the New Silk Road in Shanxi and Gansu provinces. Five types of basic planning models recommended for creation of scientific and technological parks of different functional profiles have been developed in the paper. Model A comprises scientific and technological parks with a compact layout (area of less than 2 square kilometers) located in the peripheral zones of large cities built into the city's infrastructure and they do not have practically reserves for territorial development. The model is recommended for creation of educational and scientific parks and high-tech parks. Model B comprises scientific and technological parks of medium size (area of their territory – 2–10 square kilometers) located in the nearest suburbs of large cities (up to 10 km) and these parks partially use urban infrastructure having the possibility for territorial development. The model is recommended for creation parks of industrial-logistics, high technology, light industry, precision engineering. Model C comprises scientific and technological parks of medium size (area of 10–20 square kilometers) located in the suburbs of large cities (up to 30 km), geographically and infra-structurally interconnected with international airports. The model is recommended for creating parks of high-tech, precision engineering, biochemistry that produce products which are economically expedient to be transported by airplanes (smart phones, optical fiber equipment, other high-tech devices, cosmetics, medicines, etc.). Model D comprises scientific and technological park of medium size (area of 10–20 square kilometers) located in the suburbs of large cities (up to 30 km) along transport and communication corridors of national and regional importance with its own infrastructure and territorial development opportunities. The model is recommended for creation of parks in construction industry, transport engineering, bio- and agro-technologies. Model E comprises large-scale scientific and technological parks (with area of more than 20 square kilometers) located in inter-settlement territories along transport and communication corridors of international and national importance with its own infrastructure and territorial development opportunities. The model is recommended for creation of parks for chemical industry, heavy and transport engineering. The paper has made it possible to identify common types of functionalplanning zones formed on the territory of scientific and technological parks and it provides recommendations on their correlation. Analysis of the layout for existing and projected scientific and technological parks has allowed to develop characteristic schemes of their planning organization: band, compact, dispersed.

Assuming that there are perpetual roads solution of the problem pertaining to strength and longevity of road concrete pavements are mainly determined by theoretical prerequisites which are considered as basic ones in technology for strengthening micro-structure of their top surface layer. Application of fine grain concrete with ultra-disperse additives partially helps to obtained strengthened top layer of such pavements. At the same time further search and improvement of theoretical analysis for the given problem are required for development of technological parameters. Investigations on this direction are rather insignificant and the problem continues to be considered as an actual one. There is a known method for application of colloid cement glue and activated gunite solution for strengthening binding of new and old concrete in engineering structures. However it is necessary to point out the fact that investigations in the field of protection of road concrete pavements against corrosion destructions are actually absent. Such approach restrains a wide application of the mentioned methods in engineering practice for provision of efficient maintenance of concrete pavements. In this case it is necessary to consider the existing theoretical statements on the essence of quantum structure-formation mechanics in the systems consisting of colloid-disperse particles. This approach to road concrete science is accepted a new one ant it is connected with the possibility to regulate processes of structure-formation micro-mechanics in mineral systems while creating protective surface layers in road concrete pavements. The given paper is devoted to this problem.

The method of concrete crack-resistance prediction at early age is developed at capillary shrinkage with use of approaches of fracture mechanics, which is guided by the concept of accumulation of defects in structure in the form of capillaries and cracks to their critical concentration of C_c. At the same time process at two stages is considered: on the first – process of formation and growth of defects and on the second – the process, which is directly accompanying destructions (fragmentation) at critical concentration of defects. A_s a theoretical basis of a method physical ideas of the increment volume mechanism of hollowness of cracks in the concrete model, presented as two-level structure are accepted: a matrix of the hardened cement stone with inclusions and emptiness of various form (crack) as result of the external influences, changing the intense deformed state. The main criterion of a method – the generalized total parameter of crack-resistance calculated on the basis of model schemes of growth, association, localization of cracks system, their classification by types and relative quantity in volume at the initial concentration increasing to critical, that is caused by physical processes of capillary shrinkage is established. Being based on the considered regularities of process of concrete destruction, it is offered to divide all defects of structure, both initial, and developed as a result of power and not power influences, into 5 main types. The amount of pores and cracks of the first four types depends on concrete porosity, and type V – and on the volume content of grains of small or coarse aggregate. To each type of damages, there corresponds the stress intensity factor, extent of influence and which value on the general crack resistance of material depend on quantity of this type of pores and cracks in concrete volume. The new evidence-based algorithm of crack resistance calculation at concrete shrinkage at early age by the generalized criterion, which contains the sequence of operations of calculation as for selection of structure, taking into account the factors, influencing capillary pressure and according to characteristics of properties of concrete components, its technological parameters, and for residual resource definition of concrete on its structure and properties, and also on the samples, which are selected from structures at early age is offered.

Copper pipelines are widely used while designing modern heating systems, water and gas supply of residential buildings and these pipelines have a number of advantages in comparison with steel and plastic pipelines. The main reason for limited use of copper pipes is their cost which is practically twice as much as cost of steel pipes, and four times higher than the coat of polypropylene pipes. Modern design standards in Belarus do not contain specific requirements for calculation of copper pipelines. Therefore hydraulic calculation of heating systems has been considered and analyzed on the basis of norms of Russian Federation. The drawback of all theoretical calculations presented in Russian standards is their abstraction from general laws of fluid and gas mechanics. For this reason theoretical foundations of hydraulic calculations for all pipelines have been considered and expressions have been given for determination of pressure loss due to friction and in local loss. Main flow regimes have been considered on the basis of I. Nikuradze’s experiments in order to determine linear losses and dependences for determination of friction coefficient in laminar, transient and turbulent modes have been presented in the paper. Values of local loss coefficient for main pipeline elements are given for calculation of pressure loss and the paper also shows determination of value z with due account of equipment capacity. An analysis of nomograms presented in Russian norms and researches has been carried out; shortcomings have been revealed and the ways directed on their perfection have been found. Nomograms for calculation of specific pressure losses in heating systems and internal gas supply have been constructed on the basis of natural gas and propane with due account of dependences presented in the paper. Nomograms for finding equivalent length of a single local loss have been constructed for calculation of internal gas supply systems.

The equilibrium condition for a non-thin helical wedge-shaped twin located far from the surface of the crystal is obtained. The case of an undeformed solid is considered. It is established that under such conditions a helical twin can not twin can not exist under such conditions. The result is in full conformity with generally known results for dislocation walls from helical dislocations. An approximation for continuous distribution of twinning dislocations at twin boundaries has been used in methodology for deriving an equilibrium condition. The shape of the twin boundaries has been described by functions that depend on density of the twinning dislocations at the twin boundaries. It has been assumed that the forces acting on the twin boundaries from the side of the twin dislocations are equal to zero. One degree of freedom along a twinning direction has been presupposed for twinning dislocations. Dislocation creeping effects have been excluded in the model. A calculation of stress fields for a twin has been carried out within the framework of an elasticity theory. In this case a superposition of stresses from each twin boundary has been considered. The solution of equations has been sought in the form of a polynomial. A linear approximation of such solution is considered in detail. The ем resulting equilibrium condition is satisfied for two values equal to zero that is a twin length and its width at the mouth. The result is important in the field of mechanics for twinning materials, shape memory materials, and in the development of techniques for predicting destruction and functioning of twinning materials.

. The photocatalytic activity of three systems, promising for chemical water purification technologies, was experimentally compared, based on a combination of titanium dioxide/(Fe(II, III)), applying to the model oxidation reaction of methylorange organic dye in an aqueous medium. Herewith the cases of photocatalytic systems were investigated, which are based on: a) titania hydrosol obtained by hydrolysis of titanium isobutylate; b) a similar hydrosol with addition of Fe(III) ions; c) suspension of ilmenite powder based on FeTiO₃. As a result of the investigation, the increase of the rate of destruction of methylorange by more than two times was found in the system with the introduction of a small amount of iron ions into initial suspension of the TiO₂ hydrosol (at the obtaining a medium with the Fe³⁺ concentration up to 3.7 × 10^–5 M). In the photocatalytic system, based on the suspension of pretreated (with suphation and calcination) ilmenite powder, enough high photocatalytic activity (the degree of methylorange decomposition up to 77 %) was measured but at a higher exposure than for the case of systems based on the TiO₂ hydrosol. For the photocatalytic systems of the type being investigated, a possible mechanism of increasing their oxidative activity was briefly considered, which requires an additional physico-chemical analysis.

New effective dynamic models for motion of polymeric film have been proposed in the paper. These models in contrast to known ones take in to account deformation processes which occur at a unit for polymer-film materials production. It has been shown that the deformation process of a polуmer film in intersectional area determined by its tension depends on ratio of linear section velocities and tension and deformation values in these sections. An analysis of the proposed dynamic models of polymer film motion has shown that a decrease in its deformations in every zone of the unit can be achieved both by changing ratio of input and output velocities and introducing a compensator for perturbing influences due to deformations of the film at the entrance to the zone. Possible channels for automatic control of the unit for polymer-film material production have been identified with the aim of improving quality of products. While using the proposed dynamic models it has been demonstrated that it is necessary to apply systems for automatic measuring of section rotation speed and film tension in the unit for polymer-film material production in order to ensure effective control over an extrusion process. The proposed dynamic model can be efficiently used to create an adaptive system which is applied to control a multi-motor drive of the unit for of polymer-film material production.